Carburetor



VAug. 7, 1956 T. M'. BALL 2,757,914

CARBURETOR Filed Sept. 2, -1953 3 Sheets-Sheet 1 Oncol/erin 4 z'fre i y u E'l' Uncover??? irre) 32 /j Car ,4; /i

4; INVENTOR.

BY im ud/MM2 Aug- 7, 1956 1MB/M 2,757,914

` CARBURETOR Filed sept. 2. 1953 s sneeis-sneet 2 BY Al/W Md T. M. BALL CARBURETOR Aug. 7, 1956 3 Sheets-Sheet 3 Filed Sept. 2, 1953 .M s R m5 W E M i m my 2L m 1% Y E nitecl States Patent M 2,751,914 oARBURE'ToR Thomas M. Ball, l'ooiilieltl Hills, Mich., Aassignoi" to Chrysler Corporation, Highland Park, Mich., a corporation of Delaware Application September 2, 1953, Serial No. 378,001 '25 Claims. (Cl. 261-23) This invention relates to a float type liquid fuel car- 'lburetor suitable for use on automotive vehicles and the like. The carburetor of this invention is particularly suitable for use on automotive installations in which the carburetor is subjected to fore and aft forces due to the positive and negative acceleration of the vehicle, and in which the carburetor is also subjected to horizontal lateral forces due to lateral oscillatory movement of the vehicle engine or to angular acceleration during turning maneuvers of the vehicle.

It is a known and accepted practice to design float type carburetors for operation within the specific angles of vehicle tilt to which the vehicle may be subjected when climbing or decending hills of a certain percent grade and when operating on a road surface which is laterally tilted in either direction. However, such angles of physical tilt of the vehicle do not necessarily represent the most extreme operating conditions to which the carburetor is normally subjected since the dynamic forces due to acceleration and deceleration must also be accounted for. For example, the angle assumed by the surface of the fuel within the fuel bowl may be varied as much as 4, with respect to a horizontal plane, due to fuel roll during braking, turning or acceleration of the vehicle. Therefore, it is not suicient to merely design the carburetor so that it may perform properly during operation of the vehicle over a predetermined grade or while the vehicle is tilted to a predetermined angle.

Although these dynamic disturbances are usually short in duration, they nevertheless may endure to the point where the carburetor can starve or flood one or more of the plurality of engine cylinders served thereby thus causing the engine to run irregularly or to stall.

According to one object of the instant invention, there is provided a carburetor, employing a constant level chamber and the usual metering jets and nozzles, in which o the component parts are strategically arranged and located relative to one another so as to cooperate in the desired manner under certain dynamic operating conditions which may in fact be more severe than the normal steady state conditions.

Another object of the invention is to provide a carburetor which employs a split-type iloat straddling the principal horizontal axis of the carburetor, in which,

there are main carburetor jets, a step-up piston for controlling the same, and vertical fuel wells all centrally located on or near the principal horizontal axis of the carburetor. i

A further object is to provide a carburetor as set forth in `the preceding object and which also has an accelerator pump disposed in the vertical plane containing the principal axis of the carburetor.

Another object of the invention is to provide a bowltype carburetor with a diaphragm-actuated accelerator pump which is at all points above and completely within vthe lateral confines of the carburetor fuelbowl so'that any pump diaphragm leakage or other pump leakage will drain directly back into the fuel bowl thus obviating 2,757,9145 Patented Aug. 7, 1956 any chance for fuel originally in the pump chamber to splash onto a hot manifold or other place on a hot engine.` Moreover, the pump chamber is surrounded on all lateral sides by fresh fuel and will hence have a tendency to' remain relatively co'ol and keep the fuel from boiling.l

A further object is to provide, in an accelerator pump type bowled carburetor, a discharge passage for the accelerator pump which ultimately leads to the carburetor mixing conduits but which has an interposed air gap located over the bowl so that any boiling which does occur in the pump will merely cause fuel to be returned to the bowl instead of being uncontrollably admitted to the mixing conduit.

According to a feature of at least a modified form of the principal embodiment of the invention, a bowl-type carburetor is provided with a piston-actuated accelerator pump having a discharge line terminating in a simple one-piece element containing lateral ports which not only prevent the so-called pull-over or eduction of fuel from the pump into the mixing conduit, but also provide for the direct return of any boiled and vapor-pushed fuel back to the fuel bowl.

Another object of the invention is to provide a downdraft chokeblade-containing carburetor of the type employing a float-controlled constant level chamber in which the downdraft venturi nozzles leading from the chamber incline and discharge laterally and downwardly thereby permitting the carburetor to be low and compact and yet permitting the venturis to be adequately spaced below the arc of travel of the choke blade. It is further contemplated that the high point in the thus inclined nozzle should occur at the end which is in the top of the corresponding fuel Well rather than at the venturi outlet end, and therefore the effective overflow point for the nozzle is located directly adjacent the fuel in the iloatcontrolled chamber. Accordingly, there is only a slight rise in the level of fuel in the fuel well near the nozzle when the surface of the fuel in the float chamber is rolled in a direction which would tend to pour fuel out the nozzle. Further, when the roll of the fuel surface is in the opposite direction, there is only a slight drop in the fuel level in the well relative to the noted overflow point, and the fuel emulsion in the Well need be raised only slightly in order to clear the high point of the nozzle and pass down the nozzle and into the air stream.

According to another feature of the invention, a splitfloat type carburetor for vehicles is provided in which the dimensions of the float chamber are made as small as possible in the vertical plane which contains the minor horizontal axis of the carburetor and in which dimensions in the direction of the principal horizontal axis of the carburetor are also held down.

Further features, objects and advantages will either be specifically pointed out or become apparent when for a better understanding of the invention, reference is made to the following written description taken in conjunction with the accompanying drawings in which:

Figure 1 is a view in elevation from the left side of a dual carburetor made according to the present invention;

Figure 2 is a plan view of the carburetor;

Figure 3 is a developed sectional view along lines 3-3 of Figure 2;

Figure 4 is a true sectional view along lines 4 4 of Figure 2;

Figure 5 is a plan view similar to Figure 2 but with the bowl cover and associated upper parts removed from the carburetor;

Figure 6 is a true fragmentary view in section similar to Figure 4 but with certain parts removed for greater clarity;

wFigure 7- is a true-fragmentary view in section along lines ..7-.7 of. Figure -5 Figure 8 corresponds toFigure 4 but shows a slightly modified form of accelerator pump for the carburetor;

' Figure `9 is a view similiarvt'o Figure7 but is directed tothe particular modification in form coveredby Figure 8.

The invention disclosed herein includes the subject matter whichis common to applicants copending application .Serial-No. -299,195, ffiled-July'l, `1952, and now abandoned.

In` Figures 1 3 of the drawings, a dualcarburetor 10 is shown which has a single air inlet lthrough an air cleaner '.122 and which isffitted to an'internal 2combustion engine 14 having a plurality of cylinder groups. One such group of the engine cylinders is 'served primarily by an upper intake manifold 16, and a relatively lower intake manifold 18 primarily serves another group of engine cylinders. The firing order of the engine 14 is preferably so arranged as to "cause the cylinders of the respective groupsto vfire alternately at substantially equally spaced intervals so as to maintain a substantial continuity of suction impulses in the air inlet of the dual carburetor 10. Y

` 4.The ymixture outlets of thel dual carburetor are separately connected to the inlets 20 and 22 of the manifolds 16 and 18 respectively. The dual carburetor 10 is formed 4as a single integral unit having a common air horn 24 connecting the separate mixture induction conduits generally indicated at 26 and y28, each including one or a series of venturi tubes 30 and V32. i

` A common choke valve 34 is provided to restrict the admission of air through the air horn 24for starting and for engine warm up purposes, and a partition 31 separates the mixing conduits 26 and 28 one from the other. The choke valve' '34 is controlled manually and also by a power element unit 38 which is sensitive to vheat and whichhas a .hot air connection 40 `leading thereto from a stove, not

shown,twhich may be seated on an outlet manifold of the engine .14. The unit 38 forms a so-called automatic choke, and controls an element engageable with a shaft 42 on which the choke blade 34 is mounted.

` A pair of butterfly throttle valves, 44 and 46, is mounted on a vcommon shaft 48 which is controlled .byia bell-crank lever 50. One armof the bell crank lever 50 has an opening 52 to provide a connection with the usual driveroperated accelerator pedal or`other suitable control; The other arm of the lever is connected byan adjustable link 54 to a crank 56 mounted on a Irockshaft 58 which is supported .by the body of the carburetor 10. The rockshaft 58 operates an accelerator pump hereinafter described.

fuel chamber inlet fitting 62 is provided to admit fuel into a fuel bowl 66. A suitable float controlled needle valve 64 maybe provided to control 'theow of fuel into the bowl 66. A

A 'pair of upwardly open main metering jets 68 is threadably held in the Abottom of the fuel bowl. The jets 68 are adapted to be controlled by piano wire type restricting rods 70, each of which is mounted to a common bracket 72 ysupported by `ra verticallyshiftable stepup piston 74. Each piano wire restricting rod 70 slides in a guide 7,6 so as to be movable in to and out of the corresponding main jet 68. 'The'use of piano wire for lsuch a novel application as carburetors is advantageous'bec'a'use, among other things, commercial piano wire is held to close tolerances and'standards. Also, since it is normally Vplentiful in the market, it is readily available foripu'rchaseI and is comparatively inexpensive. Thus certain economies relating to carburetor manufacture are made available and at no sacrifice in the closelyheld tolerances necessary between the orifice of the carburetor jets 68 and the-restricting rod therefor. f

A plurality of laterally open ports 78 is formedvadjacent the mouth of each of the upwardly open main jets 68. The fuel bowl 66 is covered by a'cover 47 for the carburetor andfrom the covered kfuelbowl the fuel passes downwardly through the main jets 68 and into separate .horizontaltpassages.80,-eachof whichleads into afuel Well 82. Each jet 68 thus serves one fuel well 82, which latter is crossed at an intermediate region thereof by the plane of the normal surface of the fuel in the fuel bowl when extended as at 84.

A plurality of perforationsilj, located both below and above the fuel level line 84, as extended, is formed in a perforated tube 88 which isthreadably received in the top of each of the covers, for the respective fuel wells 82. The tube 88 is exposed at 9,0 to the impact` of the air going to the downdraft conduits 26 and 28 and the pressure exerted on ,the interior of the perforated tube 88 represents the total air pressure available, that is, both the static and the velocity pressure ofthe air stream through the carburetor.

At the top of each fuel well 82 there is connected a nozzle 92 which, together with the other nozzle 92, will be seen to extend rearwardly with respect to the normal direction of travelof the vehicle, as indicated by the'arrow 94 in Figure-2. Asbest seen in Figure 3, the nozzles-92 lead laterally and downwardly with respect to the top of the fuel well 82 and into a venturi -30 or 32, as appropriate, so as to discharge substantially at the normal fuel levelfor the carburetor. It willbe noted that the high point in the fuel well 82 and thehigh point and the overflow point'for the nozzlesi92 occur immediately adjacent the-float chamber 66 for the carburetor. Thus the overflow point, indicated at 96, is such that an appreciable change of fuel -level in the `carburetor is required before the overow -by side disposition with respect to the corresponding perforated tube 88. Tube 98 has a metering restriction at the bottom end thereof and-is connected at the top by a cross passage v9.9 which leadsinto a vertically disposed passage 102 which is exposed to impact air pressure at 10,0. There are two such vertically disposed passages 102, one connected to each mixing conduit through needle valve controlled ports 104 which are adjacent the throttle blades 44 and 46. The restrictions of the ports 104 are manually controlled byvan adjustable needle valve 106 to provide the proper idling mixture for the engine.

In Figure 4, the carburetor 10 lhas two spaced-apart tubular parts 108 and 110 which rise vertically out of the floor of '.the fuel bowl 66. The part 108 slidably receives the stepup piston 74 and is connected at the bottom by means of'a passage 112 so as to be exposed to the manifold vacuum existing -below the throttle blade 44. When the throttle 44 is closed, the manifold vacuum is sufficient to hold the stepup piston 74 in a depressed position and restrict each 'main metering jet 6.8 with piano wire '70. Clockwise movement of the throttle blade 44 from closed position breaks the manifold vacuum and permits a spring 114 to raise the s tepup piston 74 and withdraw the piano wire from each of the .thus restricted main metering jets 68.

The rockshaft `Sf'mounts a link 116 thereon which by a pin and slot Yconnection 11.8"is connected to a two-piece accelerator pump plunger which i-s slidably received within the tubular part 110. The two pieces of the pump plunger are connected to o ne another by a lost motion connection 120. The arrangement .o f the lost motion connection is such that when the lower piece of the pump plunger is raised, the upper `piece may thereupon rise separately under the action of a compressed spring 126. A screw 122 connects the upper piece of the pump plunger to a movable diaphragm 124 which forms one side of an accelerator pump chamber 127.

The accelerator pump chamber 127 has a passage leading Vto a vertically disposed suction inlet 128 which extends downwardly into spaced adjacency from the bottom of the fuel bowl. The vertically disposed suction inlet 128 includes a ballv cheek valve 129 therein. The pump chamber 127 has two -separate outlets, one for each mixing conduit 26 and 28,' and each includes a ball check valve 130 and a pair of spaced-apart coaxial passages 132, 134 between which an air 'gap 138 intervenes. The air gap 138for'ms part of a vented passage 136 which leads from .inside the air horn 24 `into the fuel bowl 66. The intervening gap 138 not only prevents pullover of fuel from the pump chamber 1127,' but also permits the boiled-over fuel from the chamber 127 to pass directly back into the fuel bowl 66. v

yIn Figure 5, the carburetor is shown `to have a splittype iloat 146 incorporating an offset yoke in the central section thereof. The lloat -146 thus straddles the principal horizontal axis 140 ofthe carburetor which extends in a` direction which is parallel to the normal travelof the vehicle indicated by the arrow 94. A pair of buoyant float portions 142, 144 is connected one to the other by means of the yoke and the resulting assembly is swingably connected to a pair of out-turned trunnions or piv- -ots 149 formed by the respective ends of a curved piece of wire 148 which embraces the upstanding tubular part 110 for the step-up piston.

The upstanding tubular parts 108 and 110 together define a vertical plane containing the principal horizontal axis 140 of the` carburetor, andthe two main metering jets 68 are loca-ted in juxtaposed relationship on each side of this plane and the fuel wells `82 are likewise located one on each side of this plane. 'It will be noted also that the two fuel wells A82 are immediately adjacent a rear Wall portion 150 for the fuel bowl 66 and, in fact; the rear wall is deflected slightly forwardly at 150 so as to facilitate and accentuate the immediate adjacent rela'- tionship of the fuel wells just noted.

The compact and well-ordered arrangement'of the dual carburetor 10 of Figures 1-5 preceding, `has certain advantages-best understood from the following tables:

Where G=32.2 lit/Sec.2 Angle of roll: Body of fuel in carburetor:

.35 G corresponds to Fuel Angle 19.

.7 G corresponds to Fuel Angle 35.

Briey, the data set forth in these tables is useful in the consideration of the following design characteristics: rst, the upwardly open main jets must remain completely covered and the nozzles preferably should not overflow when the fuel rolls to either side or to the front of the carburetor to an extent in excess of 35 out of level; and second, the fuel should not completely cover the nozzles even when the fuel rolls to the rear toan extent of 19 out of level. i r

In Figures 6 and 7, itwill be perceived ythat the two main jets 68 remain completely covered under the severe fuel roll conditions produced by a .7 G brakinggdeceleration (tha-t is, 35 roll) and under the severe fuel pile-up conditions produced by a .7 G turn to the left'or to the right (that is,` a 35 roll). During a .7 G turn to the left or to the right the two nozzles 92 do not overflow and no unbalance occurs between the one group of cylin ders primarily served by the venturi 30 and the other group of cylinders primarily served by the ,-venturiSZ. Moreover, fuel does not completely coverA the nozzles 92 when, due -to a rapid acceleration of .35 G, the fuel surface rolls rearwardly to an angle of 19 from the normal plane. y l

In the embodiment shown in Figures 8 and 9, the dual carburetor 10 has a lfuel bowl 66 which is covered by a slightly modied cover 147 provided with an opening I148 in the top thereof to slidably receive a plunger 150 forming part of -an accelera-tor pump linkage. The plunger 150 is pin-connected to a link 152 which is pivotally supported by a fixed pivot 154. The fixed pivot 154 also pivotally supports a lever 156 which isformed with a transverse link engaging tab 1'58 and which'is linked* by aranci-4 means of a pull rod to a throttle-controlling crank 50. The crank 50 isv secured to a cross shaft 48 which controls the position of a pair of butterfly throttle valves 44 and 46 the vsame as described for the preceding embodiment.

The accelerator pump linkage is arranged such that when `the throttle valves 44 and 46 are in closed position, the rod 160 has a corresponding downward position, which causes the tab 158 on the lever 156 to be engaged with the link 152 andy hold the accelerator pump plunger 15d in an upward posi-tion, thereby compressing a pump return spring 162 which engages the underside of and thrusts against the cover 147. Movement of the throttle blades 44 and 46 in a clockwise direction, as viewed in Figure 8, causes the tab 158 to separate from the link 152 and permits the thrust of the compressed spring 162` against an accelerator pump piston y164 to force the piston downwardly.

The pump pis-ton 164 is shdably received in an upstanding tubular part 166 and cooperates -therewith to dene an accelerator pump chamber 167. The tubular pump cylinder part 166 rises out of the floor of the fuel bowl 66 in a manner similar to the upstanding tubular par-ts 108 and 110 described in connection with the preceding embodiment. The pump chamber 167 has an intake line 168 which is cont-rolled by a ball check valve 170 and leads from the bottom of the'fuel chamber `66 which is controlled by means of a float actuated needle valve 64 so as lto retain a constant quanti-ty of fuel therein.

The pump chamber 167 discharges through a passage 172 controlled by a ball check valve 174 and terminating in a threaded outlet element 176 which opens into 4the side of the fuel mixing conduit 26. A similar discharge passage from the pump chamber 167 is provided for the corresponding other mixing conduit 28.

The element 1176 is threadably received in 4the body of the carburetor and has a straight-through bore 178 extending axially of the element 176 and a plurality of lateral ports -180 which provide in effect an air gap in the axial bore 178. These lateral ports 180 are disposed so as to drain directlygback into the fuel bowl 66 thereby providing a passage for the discharge of fuel from the pump chamber 167 as a result of vapor push. The lateral ports 180 also communicate directly with the mixing conduit 26 thereby completing an air circuit to prevent fuel pull-over from the pump chamber 1'67 into the mixing conduit. It will be noted that the upstanding tubular part 166 `is spaced at all points from the sides of the fuel bowl 66.

The embodiment of Figures 8 and 9 is arranged similarly to the preceding embodiment and in a manner such as to permit operation of the carburetor 10 even when subjected to rather extreme forces of acceleration and deceleration. As borne out, for instance in Figure 9, the fuel nozzles 92 do not overflow under the extreme conditions of a .7 G turn to the left or the right and no unbalance occurs between the plurality of cylinders primarily served by the venturi 30 and the plurality of engine cylinders primarilyv served by the venturi 32. The main metering jets 68 remain completely covered under the severe fuel pile-up conditions produced by such a .7 G turn to lthe left or the right (that is, a 35 roll) and will further be seen to have an adequate margin of safety in this regard so as to allow for fuel splash and fuel bounce should it occur under these same conditions.

The behavior of the fuel surface in the carburetor of Figure 8 is the same in the fore and aft sense 94 as that of the carburetor of the embodimentv preceding.

As hereindisclosed, the invention is shown embodied ina single stage dual carburetor, but it is apparent that the inventionis readily adaptable to known four-barrel, two stage carburetor constructions. So also the drawing Ashows two manifolds served by one dual carburetor but self-evidently, a plurality of4 dual carburetors according tothe present improvement could advantageously be employed to serve the two manifolds which may or may not be otherwise interconnected. The venturis 30 and 32 extend upwardly to a point where there remains sufficient clearance for the proper operation of the choke valve 34 and the partition 31 extends downwardly to a point slightly below the throttle valves 44 and 46. Moreover, there is only a `slight overlap between the respective vertical extents of the partition 31 and the venturis 30 and 32, but indeed, it is not essential to the invention that the overlap last named be as slight as shown and conceivably the partitions 31 could extend upwardly to a point closely adjacent 4to the choke blade 34 and similarly the venturis 30 and 32 could extend downwardly to a location closely adjacent to the arc defined by the rotary motion of the throttle blades 44 and 46. Neither is it essential that piano wires be used as the restricting rods 70 for the main jets 6 8, even though such wires represent a decided economy compared to other known and carefully manufactured jet restricting rods.

I claim:

l. vIn a liquid fuel carburetor for a carburetted motor vehicle subject to fore and aft forces of positive and negative acceleration and to horizontal lateral forces of positive and negative acceleration, the combination comprising a pair of down draft fuel mixing conduits, venturis in said conduits, a fuel bowl for said conduits adapted to contain a main body of liquid fuel and having a fuel inlet, a oat unit in the fuel bowl having valve means controlled thereby and located in said fuel inlet for maintaining said main body of fuel within reasonable limits to a substantially uniform quantity, said float unit having two spaced apart buoyant portions connected to move together, a mechanism-carrying tubular part within said fuel. bowl betwen said buoyant portions rising out of the floor of the fuel bowl, an accelerator pumping mechanism, said tubular part being adapted slidably to receive a portion of said accelerator pumping mechanism, a step-up piston mechanism, another mechanism-carrying tubular part within said fuel bowl between said buoyant portions rising out of the floor of the fuel bowl and being adapted to contain said step-up piston mechanism, said tubular parts being spaced apart with their axes defining a vertical plane which is substantially equidistant from said two buoyant portions, a pair of upwardly open metering jets arranged in said fuel bowl adjacent the other tubular part for the stop-up piston mechanism such as to be substantially below the normal plane of the surface ofthe main body of fuel and so immersed whereby there is only a minimum drop in the fuel thereabove when the surface of the main body of fuel is forced out of normal plane in a direction tending to uncover the jets due to the aforesaid forces of acceleration, said metering jets being disposed one on each side of said vertical plane and in closely spaced adjacency to one another, a pair of fuel wells outside said fuel bowl communicating with the respective metering jets so as to receive metered fuel for the respective mixing conduits, said fuel wells being arranged in juxtaposition to one another on opposite sides of Asaid vertical plane and extending upwardly to a point located vertically above the plane of the normal surface of the main body of liquid fuel, a main nozzle extending laterally and downwardly from said fuel wells at said vertically located point aforesaid and having an outlet in the corresponding mixing conduit venturi substantially in the plane of the normal surface of the main body of liquid fuel, each said fuel well being disposed directly adjacent the body of fuel in the bowl whereby there is only a minimum rise in the fuel portion in the well when the surface of the main body of fuel is forced out of normal plane due to the accelerative forces aforesaid in a direction tending to your fuel out of the nozzle, and a pair of tubes mounted side by side in eachsaid fuel well, one tube of each pair being perforated and having a communication to atmosphere to admit air to the corresponding well above and below the normal plane of the surface of the main body of fuel, the other Pil tube of each pair incorporating a metering restriction and being effective as an .idling tube l l2. The combination according to claim l in which said first-named and second-named directions are directly opposite to one another.

3. The `combination according to claim 2 in which each said fuel nozzle and its corresponding vertically located point are arranged so as to remain uncovered according to the plane of the main fuel surface as extended, when the main body of fuel is forced 19 out of normal plane theretoward due to the accelerative forces aforesaid.

4. The combination according to claim 2 in which each said upwardly open metering jet is arranged so as to remain covered when the surface thereabove of the main body of fuel is forcibly dropped 35 out of normal plane clue to the accelerative forces aforesaid.

5. The combination according to claim l in which said first-named direction is forwardly in a fore and aft sense due to vehicle deceleration and in which said secondnamed direction is laterally at right angles thereto.

6. The combination according to claim 5 in which each said fuel nozzle and its correspondingly vertically located point are arranged so as to be uncovered and also each said upwardly open metering jet is arranged so as to remain covered when the surface of the main body of fuel ,is forced 359 out of normal plane in either the forward or the lateral directions aforesaid.

7. ln a liquid fuel carburetor for a carburetted motor vehicle subject to fore and aft forces of positive and negative acceleration and to horizontal lateral forces of positive and negative acceleration, the combination comprising a pair of down draft fuel mixing conduits, venturis in said conduits, a fuel bowl for said conduits adapted to contain a main body of liquid fuel and having a fuel inlet, a float unit in the fuel bowl having valve means controlled thereby and located in said fuel inlet for maintaining said main body of fuel within reasonable limits to a substantially uniform quantity, said oat unit having two spaced apart buoyant portions connected to move together, an accelerator pumping mechanism having portions within said fuel bowl, an accelerator pump chamber within said fuel bowl having a movable wall forming one side thereof and comprising a exible diaphragm adapted to be moved by said accelerator pumping mechanism, said movable wall being at all points above and within the vertical confines of said fuel bowl, a mechanism-carrying tubular part within said fuel bowl between said buoyant portions rising out of the floor of said fuel bowl and being adapted to slidably receive a portion of the accelerator pumping mechanism aforesaid, a step-up piston mechanism, a mechanism carrying tubular part within said fuel bowl between said buoyant portions rising out of the door of the fuel bowl and being adapted to contain said step-up piston mechanism, said tubular parts being spaced apart with their axes defining a vertical plane which is substantially equidistant from said two buoyant portions, a pair of upwardly open metering jets arranged in said fuel bowl adjacent` the tubular part for the step-up piston mechanism such as to be substantially below the normal plane of the surface of the main body of fuel and so immersed whereby there is only a minimum drop in the fuel thereabove when the surface of the main body of fuel is forced out of normal'plane in a direction tending to uncover the jets due to the aforesaid forces of acceleration, said metering jets being disposed one on each side of said vertical plane and in closely spaced adjacency to one another, and a pair of fuel wells outside said fuel bowl communicating with the respective metering jets so as to receive metered fuel for the respective mixing conduits, said fuel wells being arranged in juxtaposition to one another on opposite sides .of said vertical plane and extending upwardly to a point located vertically above the plane of the normal surface of the main body of liquid fuel, a main nozzle extending laterally and downwardly from said fuel wells at said vertically located point aforesaid and having an outlet in the corresponding mixing conduit venturi substantially in the plane of the normal surface of the main body of liquid fuel, each said fuel well being disposed directly adjacent the body of fuel in the bowl whereby there is only a minimum rise in the fuel portion in the well when the surface of the main body of fuel is forced out of normal plane due to the accelerative forces aforesaid in a direction tending to pour fuel out of the nozzle.

8, In a liquid fuel carburetor for a carburetted motor vehicle subject to fore and aft forces of positive and negative acceleration and to horizontal lateral forces of positive and negative acceleration, the combination comprising a pair of down draft fuel mixing conduits, venturis in said conduits, a fuel bowl for said conduits adapted to contain a main body of liquid fuel and having a fuel inlet, a iloat unit in the fuel bowl having valve means controlled thereby and located in said fuel inlet for maintaining said main body of fuel within reasonable limits to a substantially uniform quantity, said float unit having two spaced apart buoyant portions connected to move together, a mechanism-carrying tubular part within said fuel bowl between said buoyant portions rising out of the floor of the fuel bowl, an accelerator pumping mechanism, said tubular part being adapted slidably to receive a portion of said accelerator pumping mechanism so as to form a fluid tight pump chamber, means for establishing separate communication passages between said pump chamber and the fuel mixing conduits, each of said communication passages including an externally threaded element having a central bore arranged so as to be open at both ends of said element, said element having one of the said open ends thereof opening into a corresponding fuel mixing conduit and having lateral ports for admitting air from the mixing conduit to be bore so as to prevent unwanted eduction of fuel from the pump chamber into the corresponding mixing conduit, a step-up piston mechanism, a mechanism-carrying tubular part within said fuel bowl between said buoyant portions rising out of the lloor of the fuel bowl and being adapted to contain said step-up piston mechanism, said tubular parts being spaced apart with their axes defining a vertical plane which is substantially equidistant from said two buoyant portions, a pair of upwardly open metering jets arranged in said fuel bowl adjacent the tubular part for the step-up piston mechanism such as to be substantially below the normal plane of the surface of the main body of fuel and so immersed whereby there is only a minimum drop in the fuel thereabove when the surface of the main body of fuel is forced out of normal plane in a direction tending to uncover the jets due to the aforesaid forces of acceleration, said metering jets being disposed one on each side of said vertical plane and in closely spaced adjacency to one another, and a pair of fuel wells outside said fuel bowl communicating with the respective metering jets so as to receive metered fuel for the respective mixing conduits, said fuel wells being arranged in juxtaposition to one another on opposite sides of said vertical plane and extending upwardly to a point located vertically above the plane of the normal surface of the main body of liquid fuel, each said fuel well having a main nozzle extending laterally and downwardly from said vertically located point aforesaid and having an outlet in the corresponding mixing conduit venturi substantially in-the plane of the normal surface of the main body of liquid fuel, each said fuel well being disposed directly adjacent the body of fuel in the bowl whereby there is only a minimum rise in the fuel portion in the well when the surface of the main body of fuel is forced out of normal plane due to the accelerative forces aforesaid in a direction tending to pour fuel out of the nozzle.

I "9. A liquid fuel carburetor for use with the intake manifold of an internal combustion engine comprising a pair of downdraft throats adapted to conduct engine manifold intake air therethrough, a substantially symmetrical, enclosed liquid fuel bowl adapted to contain afsupply of liquid fuel, fuel lwells disposed between said throats and said fuel bowl in close proximity to said fuel bowl and to a vertical plane passing through the center of roll of said supply of liquid fuel, said fuel bowl and fuel wells having a fuel passage interconnecting the same, metering jets mounted on the bottom of said fuel bowl in close proximity to said plane for metering fuel into said fuel passage, vertically moving piston means mounted within said fuel bowl for controlling said jets in response to intake manifold vacuum to limit the amount of liquid fuel metered thereby, valve means for admitting fuel into said fuel bowl, a float unit in said fuel bowl for actuating said valve means to maintain a uniform liquid fuel level in said fuel bowl, said float unit comprising buoyant portions disposed on each side of said plane equidistant therefrom, an accelerator pumping mechanism having portions mounted within said fuel bowl including a pump chamber for receiving liquid fuel pumped from said fuel bowl, said chamber being situated substantially in said vertical plane, high pressure conduit means extending from said pump chamber to said throats, air vent passage means intersecting said conduit means and extending to said fuel bowl, said fuel wells having main nozzles extending therefrom into said throats, passage means for supplying liquid fuel during idling operation, a pair of tubes mounted within each fuel well in sideby-side relationship, one of said tubes being perforated and having an opening to the intake air in one of said throats, and the other of said tubes forming a fuel intake metering tube for said idling fuel passage means.

l0. A liquid fuel carburetor for use with the intake manifold o-f a throttle controlled internal combustion engine comprising at least one downdraft throat adapted to conduct engine manifold intake air therethrough, an enclosed symmetrically formed liquid fuel bowl adapted to contain a supply of liquid fuel, an accelerator pumping mechanism including portions mounted within said fuel bowl substantially in the plane of symmetry of said fuel bowl, said mechanism including a piston element mov able in response to throttle movement, a pump chamber, a diaphragm carried by said piston element covering said pump chamber, a conduit means for conducting liquid fuel into said pump chamber upon movement of said piston element in one direction, other conduit means for conducting liquid from said pump chamber under pressure to said throat upon movement of said piston element in another direction, and an air vent intersecting said other conduit means and extending from the upstream side of said throat to said fuel bowl.

ll. A liquid fuel carburetor for use with the intake manifold of a throttle controlled internal combustion engine comprising at least one downdraft throat adapted to conduct engine manifold intake air therethrough, a fuel bowl having substantially symmetrical portions for containing a supply of liquid fuel, an accelerator pumping mechanism having portions mounted within said fuel bowl substantially in the plane of symmetry of said fuel bowl, said mechanism including a piston element movable in response lto throttle movement and a pump chamber defined in part by said piston element for receiving liquid fuel therein, conduit means for conducting liquid from said pump chamber under pressure to said throat upon movement of said piston element in one direction, said conduit means including a constricted portion for injecting `fuel into said throat, and vent means intersecting said constricted portion for exposing the fuel passing through said constricted portion to engine manifold intake air, said vent means including an independent passage extending to said fuel bowl for draining excess liquid fuel to the the fuel bowl.

12. A liquid fuel carburetor for use with the intake manifold of a throttle controlled internal combustion engine comprising at least one downdraft throat adapted to conduct engine manifold intake air therethrough, a substantially symmetrical enclosed liquid fuel bowl adapted to contain a supply of liquid fuel, at least one fuel well` interposed between said fuel bowl and said throat in close proximity to saidl fuel bowl, a main nozzle extending fromY said fuel well to said throat, passage meansv interconnecting said fuel bowl and said fuel well, metering jets. mounted on said fuel bowl at theV bottom thereof, said jets being adapted to meter the flowV of fuel from said fuel bowl into said passage means, said jets and said fuel well being located in close proximity to the geometric plane of symmetry of said fuel bowl, inlet valve means for admitting fuel into said fuel bowl, and a float unit in said fuel bowl for controlling said valve means to maintain a uniform level of fuel in said fuel bowl, said oat unit` comprising buoyant portions located on either side of said geometric plane.

13. A liquid fuel carburetor `for use with the intake manifold of a throttle controlled internal combustion engine comprising at least one downdraft throat adapted to conduct engine manifold intake air therethrough, an enclosed symmetrically formed liquid fuel bowl adapted to contain a supply of liquid fuel, an accelerator pumping mechanism having portions mounted within said fuel bowl substantially in the planey of symmetry of said fuel bowl, a pump chamber enclosed within said fuel bowl and adapted to receive liquid fuel pumped from said fuel bowl by said mechanism, conduit means leading from said chamber to said throat and adapted to conduct liquid fuel therethrough under pressure during the working cycle of said mechanism, and vent passage means intersecting said conduit means, said vent passage means communicating at one end with the manifold intake air and at the other end with said fuel bowl.

14. A liquid fuel carburetor for use with the intake manifold of a throttle controlled internal combustion engine comprising at least one downdraft throat adapted to conduct engine manifold intake air therethrough, an enclosed liquid fuel bowl adapted to contain a supply of liquid fuel, a fuel well disposed in close proximity to said fuel bowl and to the center of roll of the liquid fuel therein, passage means interconnecting said fuel bowl and said fuel well, including metering jet structure for controlling the rate of fuel delivery to said fuel well, said jet structure being situated substantially on said center of roll, an idling passage means, a metering tube mounted within said fuel well in communication with said idling passage means, a perforated tube mounted adjacent said metering tube within said fuel well having one end thereof in communication with the manifold intake air, and a main nozzle extending from said fuel well at a point substantially above the level of the liquid fuel to said throat at a point proximate to the level of the liquid fuel.

15. A liquid fuel carburetor for use with the intake manifold of a throttle controlled internal combustion engine comprising at least one downdraft throat adapted to conduct engine manifold intake air therethrough, an enclosed liquid fuel bowl adapted to contain a supply of liquid fuel, a fuel well disposed in close proximity to said fuel bowl, passage means interconnecting said fuel bowl and said fuel well, a metering jet located on the bottom of said fuel bowl in communication with said passage means, said fuel well and said meteringy jet being located substantially on the center of roll of the liquid in said fuel bowl, and a main nozzle extending from said fuel well at a point substantially above the levelof the fuel in said fuel bowl to said throat at a lower level.

16. A liquid fuel carburetor as set forth in claim 13 wherein said vent passage means comprises an externally threaded element having an axial bore therein, said element being longitudinally disposed in said conduit means, and transverse passages extending through said element and intersecting said axial bore.

17. A liquid fuel carburetor for use with the intake manifold ofl an internal combustion engine comprising a downdraft throat portionV adapted to supplyl a cornbustible; fuel mixture to s aid manifold, a substantially sym- 12 metrical fuel bowl adaptedl tocontain a supply of liquid fuel,V at least one fuel well disposed in proximate adjacent relationship with respect to said fuel bowl, conduit means for transferring fuel from said fuel bowl to said fuel well, metering jets providing a communicating passage between the fuel bowl and said conduit means control means responsive to intake manifold vacuum for controlling the rate of fuel flow through said jets, said metering jets and said fuel well being disposed proximate to the common geometric plane of symmetry for said fuel bowl and said throat portion, and float control means for regulating the quantity of fuel beingA admitted to said fuel bowl, said control means havingy a buoyant portion disposed on each side of said plane of symmetry equidistant therefrom.

18. A liquid fuel carburetor for use with the intake manifold of an internal combustion engine comprising a plurality of downdraft throats adapted to supply a cornvbustible fuel mixture to said manifold, a fuel bowl adapted to contain a supply of liquid fuel, the surface level of said liquid fuel being, subjected to displacement with respect to a horizontal plane about a center of roll, said fuel bowl being partly defined by a wall structure adjacent atleast a portion of said plurality of throats, at least one fuel well disposed in close proximity to said wall structure on a side opposite to the fuel bowl interior and closely adjacent toa principal geometric plane of symmetry for said fuel bowl, said fuel well having disposed therein a perforatedl tube, an aperture in said perforated tube opening into one of said throats in the upstream direction, an idling tube disposed in said fuel well adjacent said perforated tube, and idle fuel conduit means for conducting fuel from said fuel well to a downstream portion of said throat, and passage means for transferring fuel from said fuel bowl to said fuel well, said passage means including a fuel metering mechanism for providing said fuel well with a controlled supply o f fuel from said bowl in response to variationsl in manifold pressure, said metering mechanism being s tituated adjacent said plane of symmetry and adjacent said center of roll.

19. A carburetor asset forth in claim 18 wherein said wall structure is offset toward the interior of said fuel bowl at one portion thereof, and wherein said fuel well is situated within said offset portion.

20. A liquid fuel carburetor for use with the intake manifold of an internal combustion engine comprising a plurality of downdraft throats adapted to supply a combustible fuel mixture to said manifold, a fuel bowl adapted to contain a supply of liquid fuel and being partly defined byl a wall structure adjacent at least a portion of said plurality of throats, at least one fuel well disposed in close proximity to said wall structure on a side opposite to the fuel bowl interior and closely adjacent to a principal geometric. plane of symmetry for said fuel bowl, a fuel metering means for providing said fuel well with a controlled supply of fuel from said bowl in response to variations in manifold pressure, said metering means being situated adjacent said plane of symmetry and adjacent said center of roll, said fuel bowl having disposed therein a perforated tube, an aperture in said perforated tube opening into one of said throats in the upstream direction, an idling tube disposed in said fuel well adjacent said perforated tube, idle fuel conduit means for conducting fuel from said fuel' well to a downstream portion of said throat, passage means defined in part by said metering means for transferringy fuel from said fuel bowl to said fuel well', and a fuel nozzle extending from an upper portion of' said fuel well to an individual one of said plurality of throats at a point below the upper portion of said fuel well.

21. A liquid fuel carburetor for use with the intake manifold of an internal combustion engine comprising a downdraft throat adapted to supply a combustible fuel mixture to said manifold, athrottle valve rotatably Amounted withinv a, downstream portion of said throat, anl

enclosed substantially symmetrical fuel bowl adapted to contain a supply of liquid fuel, a fuel well disposed in proximate relationship with respect to said fuel bowl substantially on a major geometric axial plane thereof, orifice means for providing a metered -ow of fuel from said fuel bowl into said fuel well, said vorilce means being situated substantially in said plane of symmetry, a fuel discharge nozzle extending downwardly from an upper portion of said fuel well `to said throat, an accelerator pumping mechanism having portions within said fuel bowl substantially in the plane of symmetry of said fuel bowl, said pumping mechanism including a variable volume pumping chamber, vented passage meansy extending from said pumping chamber to said throat for conducting an auxiliary charge of fuel to said throat, said vented passage means including an orifice element disposed in the wall of said throat, said orifice element including a discharge orilice comprising a portion of said passage means and venting apertures transversely disposed with respect to said discharge orifice, and a bypass drain passage providing communication ybetween said orifice element and said fuel bowl.

22. A carburetor as set forth in claim 21 wherein conduit means are provided for interconnecting said orifice element with an upstream portion of said throat.

23. A liquid fuel carburetor for use with the intake manifold of a throttle controlled internal combustion engine comprising at least one fuel and air mixing conduit adapted to conduct a combustible fuel and air mixture to said manifold, a fuel bowl having substantially symmetrical portions for containing a supply of liquid fuel, an accelerator pumping mechanism having portions mounted substantially in the plane of symmetry of said fuel bowl, said pumping mechanism including a piston element movable in response to throttle movement and a pumping chamber defined in part by said piston element, a pump discharge passage interconnecting said pumping chamber and said mixing conduit for conducting liquid fuel from the former to the latter, and a vent passage intersecting said pump discharge passage and extending to said fuel -bowl for draining excess liquid fuel to the fuel bowl, said vent passage providing communication between said pump discharge passage and the upstream side of said mixing conduit.

24. A liquid fuel carburetor for use with the intake manifold of a throttle controlled internal combustion engine comprising at least one fuel and air mixing conduit adapted to conduct engine manifold intake air therethrough, a substantially symmetrical liquid fuel bowl adapted to contain a supply of liquid fuel, an accelerator pumping mechanismhaving portions mounted substantially in the plane of symmetry of said fuel bowl and including a movable wall, a pumping chamber partly dened by said movable wall, said pumping chamber being in communication with said fuel bowl, a pump discharge conduit leading from said pumping chamber to said mixing conduit and adapted to conduct liquid fuel therethrough during the working cycle of said mechanism and a vent passage intersecting said discharge conduit, said vent passage communicating at one end thereof with the manifold intake air and at the other end with said fuel bowl.

25. A liquid fuel carburetor for use with the intake manifold of a throttle controlled internal combustion engine comprising at least one fuel and air mixing conduit adapted -to conduct engine intake air therethrough, a liquid fuel bowl adapted to contain a supply of liquid fuel, an accelerator pumping mechanism having portions mounted substantially in the plane of symmetry of said fuel bowl and including a movable wall, a pumping chamber partly defined by said movable wall, said pumping chamber being in communication with said fuel bowl, a pump discharge conduit leading from said pumping chamber to lsaid mixing condui-t and adapted to conduct liquid `fuel therethrough during the working cycle of said mechanism and a vent passage formed independently of said pump discharge conduit and intersecting the same, said vent passage communicating at one end thereof with the manifold intake air and at the other end with said fuel bowl.

References Cited in the file of this patent UNITED STATES PATENTS 1,685,564 Deppe Sept. 25, 1928 1,938,252 Hamachek Dec. 5, 1933 2,186,480 Ensign Ian. 9, 1940 2,212,926 Wirth Aug. 27, 1940 2,252,958 Bicknell Aug. 19, 1941 2,399,637 Jones May 7, 1946 2,628,826 Worden Feb. 17, 1953 2,655,359 Winkler Oct. 13, 1953 2,676,004 Bimberg Apr. 20, 1954 2,703,229 Henning Mar. l, 1955 

